Cooling electric lamps



Feb. 3, 19468. U 2,435,499

COOLING ELECTRIC LAMP Filed March 13, 1945 Mum 70a 5 EuSH TOA/ Patented Feb. 3, 1948 COOLING ELECTRIC LAMPS Kenneth Frederick Rushton, Bedmond, near Watford, England Application March 13, 1945, Serial No. 582,443 In Great Britain May 13, 1943 Section 1, Public Law 690, August 8, 1946 Patent expires August 16, 1963 2 Claims. 1

This invention relates to an improved holder for electric light bulbs and its object is to provide a lampholder having cooling means for the avoidance of over-heating of the bulb-holder. Quite an appreciable amount of the energy supplied to an electric lamp is given off in the form of heat, some of which reaches the lamp cap and socket, and further heat is developed at the socket contact or contacts owing to contact resistance. The effects of such heat, whatever its source, are, in the main, harmful: it gives rise to softening of the lead contact or contacts on the lamp cap, also to weakening of the contact springs and burning out of flexible leads when such are used to convey current to the lamp.

The invention, which is applicable to all sorts of lampholders, is particularly well suited for use with low voltage electric lighting systems (as used, for instance, on motor vehicles, in air-raid shelters and in small dwellings) it is not, however, restricted to such use.

The main object of the invention is to provide a self-contained electric lamp holder capable of storing a large bulk of liquid coolant. Another object of the invention is to provide an electric lamp holder in which the place at which connection is made between conductor means in the lamp holder and exterior cables leading to a source of electric current are readily accessible from the exterior of the apparatus, instead of connection with the external circuit having to be made in the interior of the lamp holder as in constructions known hitherto. A further object of the invention is to provide a self-contained liquid cooled electric lamp holder which is especially suitable for supporting an electric lamp bulb of single pole type. 7

Further features of this invention will be described with reference to a particular embodiment thereof, depicted in the accompanying drawing. Figure 1 shows the device in axial section and Figure 2 is a transverse section (sectional plan view) taken on line II--II of Figure 1.

The lampholder as illustrated is of the bayonet catch type, the socket l having the usual angular slots 2, to receive pins 3 projecting from the cap 4 of the lamp bulb 5. The lamp, being of the single pole type, has a centre contact 6 for establishing connection with the live side of the current supply (battery or mains) and the usual earthed return is effected through the cap 4 and socket I.

Th said socket is fixed in one end of a tubular member 7 extending axially through a cylindrical tank-like container 8, adapted to hold the liquid coolant, the approximate surface level of which is indicated by the reference 9. The joints between the tube 1 and the container 8 must, of course, be made liquid-tight: this can be done in any known and convenient way as, for instance, by threading the ends of the said tube and providing, packing washers l0 and nuts II to seal the joints. One of the nuts II is locked by a lock ring [2, the other by an internally threaded cap member I 3. This latter, which may be made either of conducting or of insulating material, has an openbore [4 to admit current supply wires l5 (shown as a twin flexible). A ring or bail Iii, engaged in the cap l3, affords means for suspending th device from a ceiling or the like, in a vertical position (that is to say, with the axis of the tube 1 vertical).

The centre contact 6 of the lamp 5 receives current through a conductor rod l1 extending axially through the tube I and supported therein by means of insulating blocks l8 and I9. One of the supply wires l5 (namely, the live wire) is electrically connected to the rod H, the other (neutral or earthed) supply wire being connected to the tube 1 which, of course, is in electrical contact with the socket l. Preferably, the said rod is itself constituted as a yielding contact for the centre of the socket: to this end it is made axially slidable in the insulating blocks l8 and I9 and is pressed against the lamp contact by a spring 2%] interposed between the insulator I8 and a collar 2! fixed on the said rod, the downward movement of which is limited by a preferably adjustable stop collar 22, co-acting with the insulator IS. The insulator l8 bears against an annular abutment 23 within the tube 1 and is thereby prevented from receding further into the said tube under pressure exerted by the spring 20. The insulator l9 may also be located positively in the tube 1 but in the illustrated embodiment it is assumed to have been forced tightly into the said tube.

The reference numeral 24 designates the normal filling orifice through which the liquid coolant-preferably a suitable oil--can be introduced into the container 8. As closure for this orifice a screw plug 25 (with packing washer 2B) is provided but in order to permit air to leave or to enter the container, under the influence of thermal expansion and contraction, the said plug is pierced by an air vent 21. These filling and venting provisions are effective 50 long as the device as a whole is suspended in the vertical position (as it appears in Figure 1 of the side walrofthe container. Sinceywiththe devi'ce suspended 'vertically the sur fiacelei/(e1 of the liquid coolant is above the level of the orifice 28,

the screw plug 29 is not vented but it is made? 7 interchangeable with the plug 25, so that the two plugs can be mutually transposed when the said device is to be supported horizontally "(1; -e.

with the axis of the tube 1 horizontal). Obviously 1 the interchangeable plugs can be manipulated to permit the device to be held obliquely 'at :an y

desired angle of inclination,

A preferred way of adapting Ethe davice for horizontal or oblique mounting includes replace ing the fittings l3 and It by a bracket or equivalent member secured tolthe same end of'thetlilie I (the top end in Figure 1). For instance, a fiangedtubular fitting ma y be screweddirectly bn to the said tube in pl'ace o'f the 'cap 13, the flange being holed -so that it can 'be fixed by screws or the like to ver-tical or inclined surface. Alternati-vely, the"-top end o'f the device may t'errri'in'ate in at-1 electric plug connection-6f the bayonet or the Edison screw type "capable of being engaged in a corresponding standard --socket, whether the latter beef the cord-grip (suspensib'ifl pattern or or the batten (wall fiXing) ty p The dotik'nut I2, at the bbttdl'rf 'end'of the device may-serve for the attachment of a shade or reflector for the lamp 5 or, "if the prdtruding threaded end of the tube -'I be lon enough, an additional ring nut may be use'd to function as ashade ring.

The cooled lamp'holder herein -described is*sus ceptible of various modifications 'ln respect er its constructional "details without departure -'from the esseritial features 0f thednvention. the "case df'doubl'e-pdle systems the conductor rod llwith the spring 20 and collarsiz'l flwill be 'duplicateda-ntl the two-supply wir'e's Nhwi-ll be respectively connected to the two rods (inst'ead o'f onewirebeing connectedto thetube Fl). Ph'e spaci'n g of the two-rods will, o 'fcoursefbe adapted pole lamp. Thetsliowing of electrical connection in the 'top part ofi'igure 1 is purely diagram;

4 lamp. Finally, cap fittings could be used instead of the closure plugs 26, 29.

I claim: a

1. A self-contained liquid cooled electric lampholder trorswpporting an retectn'rc llampibulb with 'asmgle pole map, compnisiirga *eylindmcal container for liquid coolant, a tube passing cenitrally and longitudinally through said container with the opposite ends of the tube projecting ilatmgahlcckszat the ends of the tube, an electric ilanrpisocket for the tube and disposed on the outside of theinsulating block at one end of the a'icentrarcorrductor rod guided axially by 5' "the apertures in the insulating blocks, stop means 2 'tonitheirodato temperate with one of said blocks itlimiting axial movement thereof, spring meansepositioned between the end of the rod and the 'dt'n'er of said insulating blocks for urging the conductor rod into the'ilamp socket to maintain resilient'coritactwith thecentral single -pole -'contacto f the cap-6f an electric lamp' bulb when the bulb *cap is-secured-Withi-n the socket; and means for'suspendingthe lamp holder in-a verticalposition, said means beingmonnected to the er-rd -of t'he tube'remote from that housing the socket.

2. A self-contained "liquid-cooled electric lamphcl'der iorsupporting "an electric lamp bulb with a single pdleoap, comprising 3, 'container for a socket =mounted-at we end -'of -said tube, -insulatingmearls moun-tedinsaid tube,=a rigitl conductor The "following references are :of :"record 'in the -file of this patent;

tUNiFBED STATES {PATENTS $0 Number Name 7 7 Date 768E827 Stewart Aug. "-30, I904 =1;4.5*7;64B Wilson, June 53923 1;53'05441 "Thomson "Mar. 17, 1925 "156'115651 Leavitt -Dec.'f21,' "1926 ii 1: z45,9c1 McKay eta-l '-Feb. 4,*1eao 252371657 Duane .Apr."-B, 1 941 2,322,945 Liabast-re June 29 1243 'beyondthe ends of the container, apertured insul-iqu'i'd-c'oolanh a t'ube extelrding'through an-erifiire dimension of said container, an electric lamp said "socket, the otherm f 'said collar means sco- 

